The '77 Trans Am was the first in years that didn't offer the 455 engine (though the '75 model was not initially offered with the big engine, it was added to the option list later that year), so a higher-output 400 was created to satisfy those seeking high performance, such as it was in 1977. Since the 455 of the previous year only made 200 hp, the high-output 400 for '77, also rated at 200 hp, seemed a worthy substitute. The standard 400 for '77 (L78) was, as you mentioned, rated for 180 hp, but the hotter version (W72) was not rated for 220 hp until the following year. The Olds 403 was rated at 185 hp, but was only used for California-bound Trans Ams in '77.
Your VIN breaks down as follows: The 2 denotes Pontiac Division of GM; the W is for Trans Am (S is for base Firebird, U is for Formula, and T is for Espirit); 87 designates a hardtop coupe, Z stands for 400 Pontiac engine, and 7 is the last digit of the model year. We changed the remaining digits of your VIN to Xs since these represent your individual sequence number. You'll note that the Z identification doesn't differentiate between the two types of 400. In your case, since you have a four-speed, your car would have been equipped with the W72 H.O. automatically, although this engine was also paired with automatics. The 180hp 400 was only mated to the automatic trans. If your car was all-original, the shaker scoop decal would read "TA 6.6" to signify the high-output engine, while 180hp cars would have "6.6 Litre" instead.
Our Mistake?Regarding your response in November's "What's Your Problem?" to the question about Ford distributor swapping, you are correct in your dissertation except for one minor point: The reader stated he has a 351M, as in Midland, commonly called 351 Modified. The 351M/400 series engines use a common distributor with the 429 and 460 big-blocks, and in fact, they have longer shafts than the small block 302s. What he needs to do is get a '75-'84, 302 Duraspark distributor. It will plug right into his old harness. This also answers the oil pump driveshaft problem. The 351 Windsor distributor is unique because of its 1.3-inch-taller deck height.Ray VairaAsh Flat, AK
In case you haven't already been flooded with mail, the November issue of Car Craft has a mistake in the answer to "Distributor Discrepancy." He can't get the distributor to work with the oil pump shaft because the 302 uses a small-block distributor while the 351M uses a big-block distributor. He needs to find a 302 distributor from the late '70s/early '80s to keep the ignition from the '79 truck. Also, a 351W distributor won't work with a 302 because the block is taller, hence a longer distributor. Nobody walks on water; we all make mistakes.Sean PerryVia the Internet
In your November "What's Your Problem?" article, there was a question concerning the 302 distributor fitting into the 351M engine. There is no way that distributor will go in there! The 351M uses a larger hex and has a larger-diameter body (where it fits into the block). He needs a 302 distributor to fit the 302 block. He could just swap the innards from the 351 distributor to the 302 distributor.Steve WilksCarrollton, TX
116-0402-TALK-A&BThanks for all your input, but if we all go back and read that question and the response, you'll hopefully find that no one asked if a 351M distributor would fit into a 302, nor was any advice offered to attempt this. The question was whether an early 302 distributor will fit in an older 302. By the way, those of you who pointed out that the 351W distributor is taller than the 302 distributor need to take another look at both of those engines. Despite the fact that the 351W has a taller deck height, the distance between the cam gear and the distributor mounting pad is basically the same (check the photos). However, you are right that the distributor for the 351W is unique, though it's the cam gear that makes all the difference.